Duplicity and the Id
Brian's mental illness is both his superpower and his curse. He grew up in a rough area and was witness to a number of brutal crimes. The inability to reconcile these events with the idea of a just and fair world lead to the development of his alter ego, Max, when he's a young man.
Unable to live in civilian life, Brian took up the name Duplicity and began attempting to create his own moral code. It's broken and fractured, not helped in the least by Max. When donning his villainous attire, Max is the Id. Everybody knows that Duplicity and the Id are connected, but not all know how.
Duplicity attempts to be a vigilante that works for justice, but his skewed moral code that still has little definition prevents him from doing any real good at all. The Id blatantly harms civilians for the sake of keeping himself amused.